= Frequently Asked Questions = == Compilation == === Compilation with gfortran fails because of unrecognized command line option `-fallow-argument-mismatch` === If this happens, please delete this option in the compile include file in `make.arch`. This option is necessary for compilation with gfortran 10, but older versions of gfortran don't seem to even know this option. === Compilation with gfortran fails with an error about a `Type mismatch` related to MPI_allreduce or some other MPI function === If this happens, please add `-fallow-argument-mismatch` in the compile include file in `make.arch` to the line 'OPT = ....'. gfortran from version 10 checks the arguments more strictly than older versions of gfortran. The apparent argument mismatch is actually allowed in the call to functions of MPI. === What does 'PE' and 'PE-local' in the code mean? === 'PE' is the common expression for 'processing element'. This relates to parallelization and usually refers to a single process or 'task' in MPI parallelization. Thus, when you read 'PE-local' in the source code, this means that some variable is local (specific) or a single process or MPI task (thus while the variable usually exist for all processes, its value can be different for each process).